let uniquePlanId = [];
jsonArray.forEach(function (item) {

if (uniquePlanId.indexOf(item['Plan Id']) == '-1') {
uniquePlanId.push(item['Plan Id']);
}
});

uniquePlanId.forEach(function (planId, index) {

let planArr = jsonArray.filter((value, index) => {
return planId === value['Plan Id']
})
console.log('gggg', planArr);

}); solution 2
let data = [{id:1, sid: 1},{id:2, sid: 3},{id:3, sid: 2},
{id:4, sid: 1},{id:5, sid: 4},{id:6, sid: 2},{id:7, sid: 1}]

let sData = []

var dataObj = data.reduce(function(r, a) {
r[a['Plan Id']] = r[a['Plan Id']] || [];
r[a['Plan Id']].push(a);
return r;
}, Object.create(null));


Object.entries(dataObj).forEach(([key, value]) => {
sData.push(value);
});

console.log(sData);